Last month, “A Game of Thrones” author George R.R. Martin drew a crowd of 2,000 in Ljubljana, Slovenia, for a book signing that lasted six hours. “That was about 1,800 more than I expected,” Martin says, a bit incredulous.

The turnout left him wondering, “If 2,000 showed up in Slovenia, what’s it going to be like at Comic-Con?”

It’s likely to be a madhouse. The veteran author has lots of hard-core fans. He’s especially well-known for “A Game of Thrones,” the first novel in his best-selling epic series “A Song of Ice and Fire” about noble families battling to claim the Iron Throne and rule the Seven Kingdoms of Westeros. “Thrones” was turned into an HBO series that just completed a highly successful first season.

And Martin’s long-awaited fifth novel, “A Dance With Dragons” will be released July 12. The timing couldn’t be better. On July 21 from 3 p.m. to 4 p.m. at Comic-Con, he’ll moderate the HBO “Game of Thrones” panel with some of the cast, including Emilia Clarke, Peter Dinklage, Kit Harington, Jason Momoa and Nikolaj Coster-Waldau.

Martin, 62, is no stranger to fame. He’s been a panelist at Comic-Con before, and in 1988 he received the convention’s coveted Inkpot Award. He’s worked in Hollywood as a screenwriter on TV shows like “The Twilight Zone” and “Beauty and the Beast.” He’s won Hugo and Nebula awards — the most prestigious for science-fiction and fantasy writers. And he was listed by Time magazine earlier this year as one of the 100 “most influential people in the world.” (Read what Time said about him here.) And that was before the HBO version of “Thrones” turned Martin into something akin to a literary rock star, bringing him a legion of new fans.

Through it all, the New Jersey native has remained a humble guy. He admits to being “fairly apprehensive” about the potential crowds he will face at Comic-Con. In 1996, when “A Game of Thrones” was released, crowds for his book signings were small. He recalls pulling into the parking lot of a bookstore in Denton, Texas, for a signing. There was no place to park. “I thought, this is gonna be a huge signing,” Martin says. “But there were two signings that day. I was in the front of the store, where about a dozen people showed up. And in the back, there was an event for Clifford (The Big Red Dog) and hundreds showed up for that.”